For Pastry: Combine flour, salt and butter. Mix in water to form dough. Knead lightly into a ball and let rest for 1 hour. Roll pastry out to cover top of pie dish, leaving enough of an overhang to form a secure edge and set aside to rest for 20 minutes.
Meanwhile, place whole chicken in pot with water to cover. Add bay leaf, thyme and parsley. Cover and simmer 25 minutes. Remove chicken and cool. Cut into 1-inch cubes.
Melt butter in saucepan over medium heat and add flour. Stir well and cook 1 minute to make roux. Strain 5/8 cup chicken stock and add to roux, whisking well, to make sauce. Season with salt and pepper and add cream and wine. Whisk again until smooth and simmer for 5 minutes.
Preheat oven to 375 degrees F. Place 1/2 of chicken in bottom of pie dish, cover with onion, then celery, then ham. Heat a little clarified butter in small saucepan and fry mushrooms for 1 minute. Add mushrooms to pie dish, along with lemon juice. Top this with remaining chicken and pour sauce on top of it all. Secure pastry to pie dish with water. Cut air hole in top of dough and paint dough with egg yolk. Bake 40 minutes.